To solve criminal event, images captured by surveillance cameras, closed circuit televisions (CCTVs), or black boxes, provide an important clue. However, it is difficult to accurately identify a face of a person who appears in a captured image from a large amount of images captured by these devices for reasons of a low resolution of the captured image, a lighting effect caused by peripheral light, and the difficulty of identification due to a covered face. Among these, in case of a low resolution of the captured image, technologies for improving or correcting the resolution of the captured image, including a super resolution (SR) technique, have been proposed.
In the SR technique, an optical limitation caused by miniaturization of a camera, a limitation in a spatial resolution caused by an insufficient number of pixels of a charge-coupled device (CCD)/complementary metal oxide semiconductor (CMOS) image sensor, and blur of a video sequence due to noise generated during image compression, transmission, and storing are removed, and a low-resolution image is corrected to a high-resolution image. An example of the SR technique is disclosed in Korean Patent Registration No. 0504594.
However, in spite of the SR technique, in actuality, it is difficult to accurately identify a face of a person who appears in the captured image by simply performing resolution correction.
Thus, a system that searches a facial type similar to a shape of a face from facial images captured at a low resolution to infer a face shape model, is required. The face shape model may serve as an initial facial composite model that may be a starting point in making a facial composite of a criminal in a situation in which a face of the suspect who appears in a captured image cannot be accurately identified. There is Korean Patent Registration No. 0504594 as a prior-art document thereof.